We just watched nine great pitches at TechStars Seattle Demo Day, taking place at the Museum of History and Industry in Seattle’s South Lake Union neighborhood.

Techstars Seattle Managing Director Chris Devore.

These entrepreneurs have been hard at work for the past three months, ironing out their business models and perfecting their pitches — it certainly showed on Wednesday evening, as I came away impressed with each pitch.

They ranged from startups using drones to improve the environment; to companies changing the way we apply for loans and trade work shifts; to entrepreneurs building new tools that improve workplace productivity; and real-life rocket scientists paving the way for communication in outer space.

But some pitches stood out more than others. Read on for our favorite picks, and scroll through to learn more about each team from recent installments of our Startup Spotlight series.

Samir Diwan had the most convincing pitch of the night. The former Microsoft engineer delivered a laser-focused presentation that clearly demonstrated the early success and ambitious potential of Polly.ai, which utilizes chatbots to help managers assess employee happiness.

Polly co-founders Bilal Aijazi and Samir Diwan. Photo via Polly.

“Polly can be trained to deliver actionable insights to help companies understand their two biggest investments: their people and the tools they use to be productive,” he said at the beginning of his pitch.

The company’s secret sauce seems to be its Slack integration. Polly.ai integrates its software into the popular enterprise communication app, allowing managers to automatically ping employees on their thoughts about the quality of internal tools, meetings, and other related processes directly within Slack.

The numbers don’t lie, either. Diwan said that there are more than 9,000 teams already using its software, representing more than 500,000 users. Polly is now the No. 1 bot in the entire Slack ecosystem — growth that has been completely organic, Diwan noted.

They say you save the best for last, and that was the case for Brett Patrontasch.

The Shyft CEO ended the evening with a strong pitch for his startup that is helping retail and service employees quickly swap work shifts, giving them a way to increase flexibility and also keep businesses from losing money.

Patrontasch noted how much money store managers lose when shifts are missed, and how much employees lose on a chance to earn wages.

“The total economic loss here is mind-blowing,” he said. “At Shyft, we can eliminate this loss.”

Heather Redman, a veteran angel investor who is backing Shyft, introduced Patrontasch and said the startup was “one of the biggest ideas I have seen” that is “a truly acute pain point for millions of people.”

Perhaps most impressive was the addressable market for Shyft. There are already 10,000 Starbucks baristas using the app, and every Old Navy store in Seattle is using Shyft.

Once one worker starts using Shyft, it can quickly spread throughout an entire organization, Patrontasch explained. He ended his pitch by noting how companies like Uber and Instacart have utilized real-time marketplaces to “completely transform traditional industries.”

“This is the transformation that Shyft is bringing to the global hourly labor market,” Patrontasch said.

Reflect CEO Alex Bilmes did this effectively and concisely, explaining how his startup gives developers an easy way to add data visualization, like charts and graphs, to their web and mobile applications.

Bilmes noted how tools like AWS, Twilio and Stripe have helped spur a culture around “buying functionality instead of building it.” He said Reflect does the same, but for data visualization, helping companies save both time and money.

“Now anyone can have team of designers, engineers, and data scientists through an incredibly simple API,” Bilmes said.

Simply Measured co-founder Aviel Ginzburg introduced Reflect, and noted how his social media analytics company is spending $5,000 per month to use its software.

“What Reflect is up to is truly unique and extremely exciting,” he said.

There seems to be demand for Reflect, with Bilmes noting how more than 1,000 companies are waiting to use the software.

You can check out all of the GeekWire profiles of the TechStars companies below — as I noted, each pitch was impressive in its own way on Wednesday, and it was definitely difficult to pick favorites.

Keepe: “Building a home repair marketplace that connects residential property managers to a vetted network of contractors for a same-day response.”

Validated: “Validated lets shops, restaurants, and other brick-and-mortar businesses buy their customers a ride or pay for their parking as a way to show appreciation, drive sales, and build loyalty.”

Validated CEO Tov Arneson.

Beam: “We make it possible for people to broadcast themselves playing games online and let their viewers control the enemies and challenges they face as they play.”

Beam CEO Matthew Salsamendi.

Taylor Soper is a GeekWire staff reporter who covers a wide variety of tech assignments, including emerging startups in Seattle and Portland, the sharing economy and the intersection of technology and sports. Follow him @taylor_soper and email taylor@geekwire.com.